The United States are one of two teams that remain undefeated after day one of the super round at the Under-19 Women's Softball World Cup ©WBSC

Japan and hosts the United States both remain undefeated after day one of super-round action at the Under-19 Women's Softball World Cup in Irvine.

The Japanese picked up two wins at Bill Barber Park, firstly beating Puerto Rico 10-0 before defeating Chinese Taipei 9-0.

Later in the day, defending champions the US outscored Canada 12-0 in four innings.

With both Japan and the US having carried over a victory from the opening round, the former now sits on three and the latter on two.

Occupying third place are Canada, who preceded their loss against the Americans by overcoming Mexico 4-0.

Japan won their two matches today ©WBSC
Japan won their two matches today ©WBSC

Mexico also suffered defeat at the hands of Chinese Taipei, losing 2-1 in the first game of the day.

Chinese Taipei are sixth behind Australia, 4-2 winners over China today, and Puerto Rico in joint fourth place.

The super round is due to continue tomorrow with a further five matches.

It is scheduled to conclude on Friday (August 16).

On Saturday (August 17), the top two teams will compete in the final and the third and fourth-place teams will contest the bronze medal game.